Landscape Ecology of Arid and Devastated Lands

Kobayashi, T. (Chiba University)

Abukuma highland had been typical satoyama area living in present days. This area was widely polluted by radioactive nuclides released from Fukushima I NPP on March 2011, and the ecosystem and local life have been deeply injured naturally and socially. Now various efforts are tried to restore the area.

For the risk management, pollution map is important. Although the air dose rates map in the 80km zone became common, local scale map of satoyama area is few yet and desired. We have continued the transect monitoring of radioactive environment across satoyama landscape. Distribution of radionuclide was so heterogeneous on any level of scale. The temporal changes of air dose rate were almost explained by the physical decay of radioactive Cesium (rCs). Consequently, spatial migration of rCs is supposed to be little. Such knowledge contributed to the protection from external radiation exposure.

By now, local people began to come back to evacuation area. In the life of satoyama-area, internal radiation exposure must be cared. Though rCs fixed by clay mineral mainly causes external exposure, ionic or colloid-combined rCs is easily absorbed by plants and transferred in ecosystem, therefore those are important in internal exposure. For the remediation of satoyama, it is important to understand the spatial flux of dissolved rCs and the diffusion in food-web.